Current electric appliances demonstrate a tendency to have a reduced weight and a smaller size, which leads to development of lithium ion secondary batteries having a high energy density. Further, lithium ion secondary batteries are used in more various fields, and thus are desired to have improved battery characteristics. In particular, the battery characteristics of lithium ion secondary batteries will become more and more important factors when the batteries are put in use for automobiles.
Patent Literature 1 discloses a non-aqueous electrolyte secondary battery including a positive electrode, a negative electrode that contains lithium or a negative electrode active material capable of occluding and releasing lithium ions, and a non-aqueous electrolytic solution containing an organic solvent and a solute, wherein the organic solvent contains an additive of lithium monofluorophosphate and/or lithium difluorophosphate.